The test block is designed according to the requirements of Technology 4 in the ultrasonic testing technology of -GB /T11345-2013 weld nondestructive testing and inspection grade evaluation standard. The test block is only applicable to the sensitivity setting when the Angle of inclination probe is 45° and the thickness of the weld is ≥15mm is detected in series. The design content of serial test block is shown in the following table.